A device for the thermal management of an optical element, comprising a gain medium (optical element) cooled by partial immersion in a bath of liquid nitrogen, is known in the prior art.
A drawback of this device is that it does not offer any possibility of temperature adjustment, the temperature being fixed solely by the temperature of the liquid nitrogen.
A device for the thermal management of an optical element comprising a plate-shaped gain medium (optical element), functioning in transmission, cooled on either side by a high-velocity helium flow, at ambient temperature (about 300 degrees kelvin (K)), is also known in the prior art.
A drawback of this device is that the helium jet pressure is likely to cause deterioration of the gain medium as well as any reflective treatment deposited on the contact surface between the gain medium and the helium flow.
Another drawback of this device is its mechanical instability, as the gas jets cause vibrations of the whole device.
Another drawback of this device is that it requires a heavy infrastructure, in particular with the provision of a system for circulating helium at high pressure.
A device is also known in the prior art for the thermal management of an optical element, in which a cold source formed by a copper plate maintained at a desired temperature is glued to a gain medium for cooling it.
A drawback of this device is that the layer of glue between the gain medium and the cold source is likely to absorb a fraction of the laser light, to heat up in consequence, and then cause deterioration of the gain medium as well as any reflective treatment that might have been deposited on the contact surface between the gain medium and the layer of glue.
Another drawback of this device is that the layer of glue between the gain medium and the cold source can alter (through chemical or mechanical effects) the gain medium as well as any reflective treatment that might be deposited on the contact surface between the gain medium and the layer of glue.